Perhaps you should try some spelling variations:
cach thoi » cac thoi, cach thuc, cach noi
cau tren » cu tren, dau tren, ca tren
danh sai » dung sai, danh bat, danh dau
mai khoi » mai khoa, tai khoa, cac khoi
hieu van » hieu va, thien van, lieu va
sai cau » lai chau, mai chau, hai chau
va danh » va dinh, va dan, va hanh
nam xuc » cam xuc, nam xua, nam thuc
thu sac » thu sach, thu san, thu xac
ky tang » ky nang, ky dang, kho tang
dai hoi » dai hoc, dai hai, dai moi
sac ky » cac ky, sai ky
xuc va » duc va, tuc va, luc va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thu sac ky tang ((dai hoi) or (((mai khoi) or (cach thoi)))). hieu van nam xuc va danh sai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sac ky tang ((dai hoi) OR (((mai khoi) OR (cach thoi)))). hieu van nam xuc va danh sai cau tren.
• Adding a wildcard symbol may retrieve word variants: thu sac ky tang ((dai hoi) or (((mai khoi) or (cach thoi)))). hieu van nam xuc va danh sai cau tren*.